Much effort has been expended to develop various fermentation processes in which single cell protein (SCP) is obtained and/or various chemical conversions are achieved by the growth of a variety of microorganisms on various carbon-containing substrates. The SCP product is useful as a protein food-source, while chemical conversions offer sources of new chemicals such as bio-polymers, pharmaceuticals, and enzymes, even commodity chemicals. In addition, genetically modified organisms can be employed to produce valuable polypeptide products.
The carbon energy substrates employed for the growth of microorganisms should be relatively cheap, readily available, and preferably water-soluble. Initially, hydrocarbons were considered as carbon energy sources for SCP. However, oxygenated hydrocarbons, such as alcohols and sugars, are more preferred as sole or partial substrates due to their relative water-solubility in an aqueous ferment, and in the reduced molecular oxygen requirements for microbial conversion-growth processes.
A limiting factor in efforts to commercialize various fermentation processes has been the cost of feedstock, cost of utilities, equipment costs and the like. Desired, therefore, is a microorganism which utilizes inexpensive feedstocks and is capable of producing single cell protein products in high yield, at relatively high growth temperatures. Such an organism would allow for the production of single cell protein material with reduced feedstock costs, as well as reduced equipment and operating costs.